If you're a university student, I would check if your school has any general lgbtqia groups that march in the parade and whether you can join them with a big giant aro sign. (For example, my university sponsors a parade contingent every year that invites any students and alumni of any identity to join).
In general, all the recommendations I made above about working with ace groups can also apply to any other non-ace groups. General student LGBTQIA groups are also another option to look into if you don't want to be at directly associated with asexuality specifically since they already have a bunch of only semirelated identities joining in together anyway.

@HotRamen is there a specific part of the west coast that you are most interested in? I run a bay area / northern california ace group and know a couple people who run other various west coast groups, so if you are interested in resource sharing with other ace groups in any particular area I could try to help get you in touch (if you aren't already). I'd be interested and available to help out if you plan to do any SF bay area events. I can also give some general advice based on my experience with organizing ace meetups.
Fwiw we I had a fairly spontaneous one-off aro ace meetup here for ASAW that was hastily planned because I forgot what week it was, and even with that poor planning I got a good 8 people or so. So I think if you reach out to local ace and LGBTQIA spaces to start off with, there might be more interest than you think, especially if you are near a large city.
As far as general meetings go, I would recommend considering a meetup.com group as well as a facebook page - my local ace group that I run has had a lot of success with people finding us through meetup that wouldn't have found us otherwise. You do need a paid subscription to start a new meetup group, but, existing hosts can host I think up to 3? groups, so if you can find another meetup group who is willing to help get you off the ground, their organizer may be able to set up the group and make you a co-mod to avoid additional fees. (For example, the SF ace meetup group and the LA ace group are currently do this)
I'd also recommend scheduling a bunch of initial meetups around things that you like to do anyway, like going to a cafe for lunch or to read a book, or walking in a park, seeing a movie, getting ice cream, etc. Just bring a good book or some podcasts so that even if no one shows up to the first few you can still make it a fun outing for yourself. If you can have that at a regularly recurring time (like the X o'clock on the Nth saturday or sunday of the month) that can help get the initiative going to encourage other people to also show up, though it may take some time.
For pride parades specifically, I definitely recommend trying to find an ace group to mooch off of if possible - parade registration fees can be a couple hundred dollars in some of the bigger cities, but if you march with another group but have two signs and leave like a 15 foot gap in the middle of the two halves of your group it's much cheaper
The other route I would suggest is to see if there are any "alternate" pride marches in your area that are in smaller suburbs or cities near a main city - for example, Oakland pride vs. SF pride or Long Beach pride vs. LA Pride for some examples. These are often cheaper, less crowded, and less intimidating for a first time group. They are also usually on a different weekend than whenever the pride march in the biggest city in your area is.
I also have some notes on planning pride parade groups here - it was originally made for ace groups but a lot of the advice applies to any small, new groups.

Does anyone know if there are any existing projects that have created / are aiming to create any kind of aro history timelines?
I'm interested in maybe, eventually creating some kind of timeline / reference page with some tidbits of aro history but I don't want to reinvent the wheel if I don't have to, so I'm wondering if anyone knows of anything pre-existing, or if there's anyone already working on something like this that would be interested in some help.
Specifically, the kinds of things I'm thinking to include are:
Timelines of various attempts at aro forums, including when they were founded and when they collapsed (including things like the [ace] aromantic forum-motion forum, aroplane, the first arocalypse, the second (current) arocalypse, the AVEN a/romantic orientation subforum and it's false starts, etc.) especially with notes on which were aro ace specific and which were general aro.
The beginnings (and ends) of various aro activist efforts and resource pages (like ASAW, the now defunct Coalition for Aromantic Visibility, the aromantic wiki, etc.)
Outlines of the three main aro flag proposals and when they mostly saw use
The evolution of various aro community and related vocabulary, like "aromantic", "grayromantic", "gray-aromantic", "qoiromantic", "squish", "queerplatonic", etc.
When and where aro characters have appeared in mainstream media (jughead, that one dude from the cassandra clare books)
[possibly] early media coverage of aromanticism, if it seems notable, and misc. things like aromantic getting added to the OED
I have access to most of the sources needed for a lot of this info already, the tricky part is just getting it all organized and figuring out how to work it into something for people to actually use and understand. Also, if it sounds like I've forgotten some category of events or spaces that you think would be interesting to include, please let me know!
Other things that I'm not as familiar with, however, that I'd be especially interested in learning about if anyone would be willing to share their notes:
Any influential aromantic pages or groups on facebook, reddit, twitter, or other non-tumblr or wordpress social media (I know absolutely nothing about what is or isn't going on on facebook in particular)
Any non-english language activity
Explicit canon representation of aro characters besides bojack and rafael (I suspect there have been some webcomic and YA novel characters by now, but I don't follow either of those very closely. Also, does anyone know if Bojack has any aromantic characters? I know they named drop the word but not sure if they ever link it to any specific characters, and I don't really want to actually watch the whole show)
Also, if anyone has questions about aromantic history, or is intrigued by any of the mentions above and would like a link or to learn more, feel free to post a comment here and I'll try to see if I can answer them (though I might be slow) - any thing that gets me motivated to work on this more is good.

I know this is a bit late, but I've posted my own response about some of the reasons for going with the current carnival timing / proposed topic here. I don't really do forums much these days, especially after getting burned out on AVEN, which is part of why I was interested in trying to promote more centralized spaces for aro blogging conversations, so I wasn't aware of the attempts to communicate issues here, and apologize for being so late to respond.
I know that there's a lot of tension between various parts of the aromantic community, and I had also hoped that the topic could be an opportunity for a sort of airing of grievances exactly like what people have already to posted - to some extent I think this is a reckoning that was going to have to happen sooner or later in any attempt to connect more disparate parts of the aro community, and I had hoped to just get it over with instead of leaving it simmering just under the surface to build into more and more resentment. It's clear now though that the timing may have been too soon for that, so that's also on me.

I'm not sure if you're also interested in more resources or blogs, but if you are also interested in more people to talk to about spanish language discussion of aromanticism, Mundo Heterogéneo is a bilingual english/spanish blogger who's been doing some writing about aromanticism for the carnival of aros. I know Chrysocollatown has also written a bit about aromantic visibility at their mostly-spanish-language blog - they'd also probably be a good person to check with if you are looking for additional resources since they do a fair amount of both research and activism. (I'm a lame english monoloingual, so I can only understand bits of those posts, but I enjoy both of their english writing).
But as far as topics, getting interviews/quotes from a bunch of different aro people to feature a variety of experiences could be one interesting type of content.

Oh, this is really cool! It's interesting to see how explicitly aro ace they made the story coding in this edition. For anyone who's curious about the original japanese version and some of the vocabulary involved, there was some talk about it on tumblr a couple years ago.
The english fan scanlation stopped only a few chapters in, so I'm curious to see if it ever gets an official license here.